Technical Field
The present invention relates to a furnace-heating combustion apparatus comprising: an air box connected to a furnace wall to be communicated with a flame passing hole formed in the furnace wall, the air box including a cylindrical tube section on the side of the furnace wall and receiving supply of combustion air from a combustion air supplying means; and an elongate burner in the form of a double-tube having, at the center portion thereof, a fuel conduit for flowing gas fuel and having, at the outer circumferential portion thereof, a primary air conduit for flowing primary air, the elongate burner being provided to extend through a rear wall portion of the air box disposed away from the furnace wall, wherein a leading end portion of the burner is disposed inside the air box in such a manner that a secondary air conduit for flowing air present inside the air box as secondary air is formed between the outer circumferential face of the leading end portion of the burner and an inner circumferential face of the tube section.
Background Art
Such furnace-heating combustion apparatus as described above is for use in heating various types of furnaces such as a melting furnace for melting an object to be melted such as glass, metal or the like or a heating furnace for heating an object to be heated such as a forged article.
As an example of such furnace-heating combustion apparatus as above, there is known one configured as follows. In this known apparatus, the burner includes a fuel-supply tubular body provided along the whole length of the burner and forming a fuel conduit and an air-supply tubular body disposed to surround an area from a position located outside an air box to a leading end portion and forming a primary air conduit between the fuel-supply tubular body and the air-supply tubular body and forming also a secondary air conduit between the air-supply tubular body and a tube section of the air box. And, an amount of combustion air from a blower as a combustion air supplying means is supplied to the air box and also to a portion of the air-supply tubular body located outside the air box (see e.g. Japanese Unexamined Patent Application Publication No. 2002-13704 (FIGS. 1 through 3).